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Cleanups for Creativision.

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This commit is contained in:
Christian Groessler
2017-02-01 19:46:04 +01:00
parent 0b2a699b46
commit a08f905224
22 changed files with 291 additions and 314 deletions
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66
libsrc/creativision/clrscr.s
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@@ -4,38 +4,38 @@
;* NB: All screen functions assume Graphics Mode 1 in a default configuration.
;* Therefore, this is hard coded to use $1000-$12FF as screen VRAM.
.export _clrscr
.include "creativision.inc"
.export _clrscr
.include "creativision.inc"
_clrscr:
sei ; Disable interrupts. Default INT handler reads VDP_STATUS
; and would lose any setup done here.
lda #$00 ; VRAM offset low
sta VDP_CONTROL_W
lda #$50 ; VRAM offset high ($10 OR $40)
sta VDP_CONTROL_W
lda #$C0 ; Space from ROM setup
ldx #0
ldy #3
L1: sta VDP_DATA_W
inx
bne L1
dey
bne L1
cli ; Let interrupts go again
lda #0
sta CURSOR_X
sta CURSOR_Y
sta <SCREEN_PTR
lda #$10
sta >SCREEN_PTR
rts
sei ; Disable interrupts. Default INT handler reads VDP_STATUS
; and would lose any setup done here.
lda #$00 ; VRAM offset low
sta VDP_CONTROL_W
lda #$50 ; VRAM offset high ($10 OR $40)
sta VDP_CONTROL_W
lda #$C0 ; Space from ROM setup
ldx #0
ldy #3
L1: sta VDP_DATA_W
inx
bne L1
dey
bne L1
cli ; Let interrupts go again
lda #0
sta CURSOR_X
sta CURSOR_Y
sta <SCREEN_PTR
lda #$10
sta >SCREEN_PTR
rts